1. Department of Materials Science and Engineering, Hanbat National University, Daejeon, South Korea
2. Nano Convergence Technology Division, National Nanofab Center (NNFC), Daejeon, South Korea
3. School of Electrical Engineering, KAIST, Daejeon, South Korea
4. Department of Electronics Engineering, Chungnam National University, Daejeon, South Korea
5. Samsung Electronics Company Ltd., Modem Research and Development Group, Network Business, Suwon, South Korea